The goal of our Training and Research in Environmental Health in the Balkans (TREHB) project, as stated in our 1996 application, is "to create, through specialized training and research, a core group of environmental and occupational health (EOH) scientists who will eventually impact the approach to environmental problems in their countries through epidemiological research, environmental monitoring and engineering, and induced policy shifts for environmental hazard reduction, chronic disease prevention, and the control of injuries in the workplace." In the first project cycle (1996-2001), our primary focus was on Bulgaria, while in the second cycle (2001-present) we added activities in Romania and Serbia and Montenegro. We have developed a "capacity-building" approach involving a) training workshops focused on practical skills for young and midcareer scientists, b) specialized research skills training in the US for graduate students and young professionals, c) advanced training in the US for senior scientists, d) field research and training activities on actual environmental and occupational health problems, e) development and execution of traditional collaborative research projects and f) providing assistance for institutions to improve their research and graduate education capabilities. Our general strategy has been to offer training in basic skills and approaches through workshops, and selectively move those with the most potential into other forms of participation according to their interests, needs and capabilities. We propose to continue and expand this approach in a proposed third cycle to a) build on established research capacity in Bulgaria to secure increased external support, b) focus our efforts in Serbia and Montenegro and Romania on building greater research capacity, c) build on our preliminary efforts to expand the program into Croatia and Macedonia. We are proposing a mix of training and research activities according to the needs of each country, a new research focus on problems related to rural health and the mining and mineral processing industries, and a regional professional organization and open-access journal to encourage multi-country collaborative approaches. This effort is relevant to global public health protection efforts as it seeks to build local capacity to assess and manage environmental and occupational health threats, thereby allowing action to be taken in the early stages of a problem, and in some cases preventing problems from spreading across boundaries.